The present invention relates to a method for making comparisons between reference data elements and data elements proceeding or issuing from a file.
A process of iterative and simultaneous comparison between reference data elements and data elements proceeding from a file is described in U.S. Pat. No. 4,053,871.
A file upon which a comparison is to be carried out includes reference data elements consisting of items of information, for example, of octets. The data elements are of fixed or variable length. For variable length data elements, it is necessary to add to each data element a special character to indicate its end. The data elements, in turn, are gathered in sequences each of which is identified by a particular label (or ticket, or title, . . . ) called a special data element. The sequences may be fixed or variable length, that is to say, may include a number of data elements which may be fixed or not. A special character is added to each sequence which has a variable length to indicate its end.
An iterative and simultaneous comparison is performed which consists of testing for and recognizing a relationship between each data element, special or not, derived from a source and a number of reference data elements, simultaneously. The relationship is, for example, a relationship of equality, of inequality, of bracketing, etc.
For this purpose each data element from the source is matched, item of information by item of information, with the reference data elements which have been entered into successive lines of a reference table. The results from the matchings are combined in order to provide the result of the comparison which determines which information is to be stored.
U.S. Pat. No. 4,443,860 relates to a method of control which enables the method of comparison described above to be applied to items of information contained in a file having any construction or file arrangement whatever. The method is capable of operating at the frequency at which the items of information are received from the source, without an external preprocessing marking. The controlling and simultaneous execution of the elementary functions connected with the comparisons and the storage operations are carried out, without interrupting the retrieval of information from the file. The elementary functions which are to be executed simultaneously relate to: the localization (identification), processing and transfer of the items of information from the source; the sequential linking of the groups of simultaneous operations; and the tests concerning the results obtained from the preceding comparisons.
The method and contents of the above mentioned U.S. Pat. No. 4,443,860 are herein incorporated by reference. Its method essentially consists of the following steps:
(a) Reference data elements are recorded in a reference table with data elements of different types being stored vertically in different horizontal zones of the table. The reference data elements are stored in the same order that the sequences of data elements which they are to be compared appear, not necessarily in a consecutive fashion, in the source file. Each horizontal zone of the table contains reference data elements of the same type drawn up in their turn vertically by columns. For example, a given zone will contain the five words of the sentence "I want to go home", each word (reference data element) being located in a respective line of its column. All of the words in this zone are related and such that the reference data elements will be considered of the same type. These elements will be compared to input data elements also of the same type.
(b) In a control memory, the following is recorded line by line:
(1) First items of control information including, firstly, items of control information relating to the comparison to be carried out between input data elements of the same type from the source file and reference data elements located in a horizontal zone of the table corresponding with the line in the control memory in which the said items of comparison control information are recorded, and secondly items of control information relating to the storage of input data elements proceeding from the source file, and
(2) second items of information for control of operations to be carried out at the end of the comparison or comparisons effected with one or more items of input data elements from the file and/or from the storage of one or more items of input data elements from the file, the said items of information for control of operations including items of jump control information for controlling the linkage of the processes to be carried out;
(c) items of information from the source file are consecutively received; and
(d) the operations are executed which correspond with the first items of control information from a first line in the control memory, then the operations which correspond with the second items of control information from this line, among them especially the linkage onto another, not necessarily consecutive, line in the control memory and if necessary onto a horizontal zone of the reference table corresponding with this other line.